aura: Implement new app list mock.

ash/app_list/app_list_item_group_model.h

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef ASH_APP_LIST_APP_LIST_ITEM_GROUP_MODEL_H_
-#define ASH_APP_LIST_APP_LIST_ITEM_GROUP_MODEL_H_
-#pragma once
-
-#include <string>
-
-#include "ash/app_list/app_list_item_model.h"
-#include "base/basictypes.h"
-#include "ash/ash_export.h"
-#include "ui/base/models/list_model.h"
-
-namespace ash {
-
-// AppListItemGroupModel holds a list of AppListItemModels.
-class ASH_EXPORT AppListItemGroupModel {
- public:
-  typedef ui::ListModel<AppListItemModel> Items;
-
-  explicit AppListItemGroupModel(const std::string& title);
-  virtual ~AppListItemGroupModel();
-
-  void AddItem(AppListItemModel* item);
-  AppListItemModel* GetItem(int index);
-
-  const std::string& title() const {
-    return title_;
-  }
-
-  int item_count() const {
-    return items_.item_count();
-  }
-
- private:
-  const std::string title_;
-  Items items_;
-
-  DISALLOW_COPY_AND_ASSIGN(AppListItemGroupModel);
-};
-
-}  // namespace ash
-
-#endif  // ASH_APP_LIST_APP_LIST_ITEM_GROUP_MODEL_H_